Aberrant cervical thymus: imaging and clinical findings in 13 children

To investigate the imaging and clinical findings of aberrant cervical thymus, especially validating the usefulness of ultrasound (US).

The imaging and clinical findings of 13 children with aberrant cervical thymus were reviewed. Imaging studies were investigated for the location, size, composition, and shape with special emphasis on US characteristics. Medical records were reviewed for patient demographics, clinical presentations, and management.

There were 10 male and three female patients (age range 1 month to 12 years; mean 3 years). Nine children (69%) were younger than 1 year. The most common presenting symptom or sign was palpable, cervical, non-tender mass or swelling. The most common site was the submandibular area. The mean of the maximal diameter was 3.5 cm (range 1.5-10 cm). The composition was solid (n=12) and solid and cystic (n=1). All lesions showed well-defined, angular margins with moulding over adjacent structures. On US, the echogenicity of the solid portion was identical to that of the mediastinal thymus in all cases, demonstrating the characteristic internal echo pattern.

Although rare, aberrant cervical thymus usually occurs as a well-defined, solid mass most frequently at the submandibular area in infants and young children. US is indicated as the initial imaging mode for assessment and may be the only technique required.